China angrily hit back at allegations that its 16-year-old swimming prodigy Ye Shiwen could only have carried out her recent record-breaking performances with the help of illegal drugs.

Officials were left fuming after an American swimming coach suggested Shiwen’s astonishing times were “unbelievable”, whilst Chinese fans flocked online to decry what they saw as prejudice against their increasingly dominant athletes.

The furore has left the United States struggling to defuse a potentially disastrous diplomatic row with Beijing that could have wider repercussions outside of sport.

Ye smashed a world record in Saturday's women's 400 metre medley - swimming the final 50 metres of the race faster than the men's champion, American Ryan Lochte.

Chinese officials, fellow swimmers and anti-doping experts – and even the teenager’s father – flocked to her defence today arguing that the teenager has always previously passed anti-doping tests and that it was not unusual for young swimmers to shave seconds off swimming records when they are at their peak.

“Ye Shiwen has been seen as a genius since she was young, and her performance vindicates that,” Xu Qi, the head of the Chinese swimming team, told the Chinese state news agency Xinhua. “If there are suspicions, then please lay them out using facts and data. Don't use your own suspicions to knock down others. This shows lack of respect for athletes and for Chinese swimming.“

Jiang Zhixue, the anti-doping chief of China’s General Administration of Sport, added: “I think it is not proper to single Chinese swimmers out once they produce good results. Some people are just biased. We never questioned [American swimmer] Michael Phelps when he bagged eight gold medals in Beijing.”

Her father Ye Qingsong blamed the “biased” reaction of the international media for the question marks over his daughter’s performance. “A lot of different people had to provide all kinds of help for this result to be possible,” he said. “The western media has always been arrogant, and suspicious of Chinese people.”

Allegations of doping are a sensitive issue at the best of times but the Chinese are particularly touchy about the subject. In the 1990s their swimmers dominated the sport until a series of high profile athletes tested positive for banned substances. Two decades on the Chinese are back on top with what they insist is a “zero-tolerance” approach to doping.

The International Olympic Committee also came out in support of Ye. Under the organisers’ anti-doping rules, all medal winners are automatically tested. Today IOC spokesman Mark Adams hinted strongly that Ye’s test came back negative saying he would only comment if a substance was found. He also expressed disappointment that people had begun questioning Ye’s performances. “We need to get real here,” he said “These are the world's best athletes competing at the highest level and we've seen world records all over the place.”

Lord Moynihan, chair of the British Olympic Association, said the World Anti Doping Agency had cleared Ye. “We know how on top of the game Wada (World Anti-Doping Agency) are and Wada have passed her as clean,” he said, “That's the end of the story. And it is regrettable there is so much speculation out there. I don't like it. I think it is wrong. Let us recognise that there is an extraordinary swimmer out there who deserves the recognition of her talent in these Games.”

On Weibo, the Chinese equivalent of Twitter, internet users left hundreds of thousands of angry messages with Ye Shiwen trending as the most popular topic for much of the day.

Much of their ire was directed at the UK because the British media had been the first to carry the doping allegation quotes from American swimming coach John Leonard.

“You Brits, don't join the Olympic Games if you can't afford losing,” wrote one Weibo user in Sichuan. Another user added: “The only motive for the western media to attack Ye Shiwen is because she is Chinese.”